<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>hello world</title>
    <script src="./sdk/react.development.js"></script>
    <script src="./sdk/react-dom.development.js"></script>
    <script src="./sdk/babel.min.js"></script>
</head>

<body>
    <div id="root"></div>

    <script type="text/babel">
        const arr2 = [
            'hello React',
            'hello Vue',
            'hello Angular',
        ]

        class HelloWorld extends React.Component {
            render() {
                return 
                <div>
                    {
                        // xxxx
                        arr2.map((item, index) => {
                            return <h1 key={index}>{item}</h1>
                        })
                    }
                </div>
            }
        }
        ReactDOM.render(<HelloWorld />, document.getElementById('root'));
    </script>
</body>

</html>